• 한국수자원학회논문집
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• 제42권4호
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• pp.343-353
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• 2009

본 연구의 목적은 댐방류에 의한 하류하천의 수질개선효과를 대체댐이 아닌 하수처리시설을 대체시설의 비용으로 적용하여 국내 실정에 맞게 편익으로 산정하는 방법론을 제시하는 것이다. 이를 위해 댐을 대체하는 시설은 댐의 방류수와 동일한 기능을 제공해야 하고, 두 시설간의 비용을 객관적으로 비교할 수 있어야 한다. 본 논문은 대체비용법을 이용하여 수질개선편익을 산정하기 위해 대체시설(하수처리장)의 비용 산정방법, 비용 편익분석 관련 기준인 내용연수와 대수선비율의 근거를 제시하였다. 사례연구로서, 낙동강수계의 내성천에 계획한 송리원댐의 수질개선편익을 산정하였으며, 그 결과는 연평균 방류시 644,006 백만원, 수질악화기의 최대방류시 1,351,526 백만원으로 산정되었다. 본 연구방법은 환경개선용수 공급사업시 실무에서 활용 가능한 수질개선 편익산정방법이 될 것으로 기대된다.

• 한국물환경학회지
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• 제27권5호
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• pp.670-679
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• 2011

Chlorophyll-a is a major water quality indicator for an algal bloom in streams and lakes. The purpose of the study is to estimate chlorophyll-a concentration in tributaries of the Seonakdonggang by an artificial neural network (ANN). As the tributaries are ungauged streams, a watershed runoff and quality model was used to simulate water quality parameters. The tributary watersheds include urban area and thus Storm Water Management Model (SWMM) was used to simulate TN, TP, BOD, COD, and SS. SWMM, however, can not simulate chlorophyll-a. The chlorophyll-a series data from the tributaries were estimated by the ANN and the simulation results of water quality parameters using SWMM. An assumption used is as follows: the relation between water quality parameters and chlorophyll-a in the tributaries of the Seonakdonggang would be similar to that in the mainstream of the Seonakdonggang. On the assumption, the measurement data of water quality and chlorophyll-a in the mainstream of the Seonakdonggang were used as the learning data of the ANN. Through the sensitivity analysis, the learning data combination of water quality parameters was determined. Finally, chlorophyll-a series were estimated for tributaries of the Seonakdonggang by the ANN and TN, TP, BOD, COD, and temperature data from those streams. The relative errors between the estimated and measured chlorophyll-a were approximately 40 ~ 50%. Though the errors are somewhat large, the estimation process for chlorophyll-a may be useful in ungauged streams.

• 대한환경공학회지
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• 제30권12호
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• pp.1225-1230
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• 2008

이 논문에서는 팔당호에 행해진 수질관리 정책의 효과를 분석하기 위하여 계절 맨-켄달 경향분석법(Seasonal Mann-Kendall Trend Analysis)을 사용한 새로운 접근법으로 팔당호로 유입되는 주요 지류중 하나인 경안천의 수질을 정책 전과 후로 나누어 비교 분석하였다. 1992년부터 2005년까지 월별로 측정된 BOD, COD, 총인 및 총질소의 자료들을 이용하여 1998년 한강특별대책 시행 전과 후의 켄달 기울기(Kendall slope)를 비교하였고, 그 결과 한강특별대책이 경안천 하류의 수질 개선에는 효과가 있었으나 상류의 수질 개선에는 큰 효과를 거두지 못하였음을 밝혀냈다. 이러한 결과는 이전에 행해진 경안천 수질 관련 연구들의 결과와 잘 일치하는 것으로 보아, 이 연구에서 사용된 수질의 장기 경향 분석을 통한 정책의 효과를 판단하는 접근법은 앞으로 유용하게 사용되어 질 수 있으리라 판단된다.

• 한국물환경학회지
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• 제23권6호
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• pp.863-871
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• 2007

Spectroscopic characteristics of river water from four major watersheds in the Ulsan area were measured to examine their potential for estimating water quality parameters. The total 176 river samples were collected from 44 sites of small streams within the watersheds during the year 2006. Spectroscopic characteristics investigated included protein-like fluorescence (FLF) intensity, fulvic-like fluorescence (FLF) intensity, terrestrial humic-like fluorescence (TLF) intensity, UV absorbance at 254 nm, and UV absorbance difference at 220 nm and 254 nm. Protein-like fluorescence intensity showed linear relationships with biochemical oxygen demand (BOD), chemical oxygen demand (COD), total phosphorous (TP) concentrations of the samples with the correlation of 0.784, 0.779, and 0.733, respectively. Due to the UV absorption characteristics of nitrate at 220 nm, UV absorbance difference at 220 nm and 254 nm was selected to represent total nitrogen (TN) concentration. Exclusion of some samples with PLF intensity higher than 5.0 improved the correlation between the UV absorbance difference and TN as demonstrated by the increase of the correlation coefficient from 0.392 to 0.784. Instead, for the samples with PLF intensity lower than 5.0, the highest correlation of TN was achieved with UV absorbance at 254 nm. The results suggest that PLF intensity could be used as the estimation index for BOD, COD, and TP concentration of river water, and as the primary screening index for the prediction of TN using UV absorbance difference. Some BOD-based water quality levels among the river water were statistically discriminated by the PLF intensity. Low p-values were obtained from the t-tests on the samples with the first level and the second level (p=0.0003) and the samples with the second and the third levels (p=0.0413). Our combined results demonstrated that the selected spectroscopic characteristics of river water could be utilized as a tool for on-site real-time monitoring and/or the primary estimation of water quality.

• 한국농공학회지
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• 제45권2호
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• pp.116-125
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• 2003

Predictions of stream water quality require both estimation of pollutant loading from different sources and simulation of water quality processes in the stream. Nonpoint source pollution models are often employed for estimating pollutant loading in rural watersheds. In this study, a conjunctive application of SWAT model and WASP model was made and evaluated for its applicability based on the simulation results. Runoff and nutrient loading obtained from the SWAT model were used for generating input data for WASP model. The results showed that the simulated runoff was in good agreement with the observed data and indicated reasonable applicability. Loading for the water quality parameters predicted by WASP model also showed a reasonable agreement with the observed data. It is expected that stream water quality could be predicted by the coupled application of the two models, SWAT and WASP, in rural watersheds.

• 한국농공학회지
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• 제42권5호
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• pp.94-102
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• 2000

Investigated was the effectiveness of a constructed wetland system on water quality in Hwa-Ong estruarin reservoir, located in Hwasung-Gun, Kyunggi-Do. Procedures for estimation of pollutant loading from watershed and required area for natural systems, and simulation of corresponding reservoir water quality were reviewed. Generally, simulated reservoir water quality was within the reasonable range, and about 15% of total polder farmland was required to meet the agricultural water quality standards. The model was applied based on the current loading condition without additional treatment systems. Wetland system is an ecologically sound treatment system. Therefore, natural systems can be an alternative measure for water quality improvement in polder projects. The area for natural systems was estimated using literature value which might be acceptable at the planning stage. However, pilot system and its experimental data are requisite for large scale field application. WASP5 was proved to be a useful and versatile model, and its application to estuarine reservoir water quality simulation was thought to be appropriate.

• 물과 미래
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• 제35권5호
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• pp.51-59
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• 2002

In recent years the human impact on the environment becomes increasing lift threatening, calls for the better management of resources. In field of water quality of river flow, the best way to conserve water quality is specific efforts to control the pollutant loadings and treat the loadings in the basin to reduce the discharge of pollutant loadings to river. But in general the water quality influenced by the dam discharge. Especially in dry season, it is more dominant way to improve the water quality which contaminated with the pollutant loadings from the basin. The dam discharge amounts of the 2 dams in the Keum River that maintain the down stream water quality were estimated for the year of 1999, 2001, 2006, 2011, in case of irrigation and non-irrigation seasons. The pollutant loadings for the basin are estimated with the planning of treatment plants construction schedule for every sub-basins. The river flow rates were considered low flow as 2.33 year low flow and 10 year low flow. The QUAL2E model was used as a tool of simulation.

• 한국농공학회논문집
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• 제59권3호
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• pp.83-96
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• 2017

This study presented a surface water quality modeling framework considering the spatial resolution of pollutant load estimation to better represent stream water quality characteristics in the Saemangeum watershed which has been focused on keeping its water resources sustainable after the Saemangeum embankment construction. The watershed delineated into 804 sub-watersheds in total based on the administrative districts, which were units for pollutant load estimation and counted as 739 in the watershed, Digital Elevation Model (DEM), and agricultural structures such as drainage canal. The established model consists of 7 Mangyung (MG) sub-models, 7 Dongjin (DJ) sub-models, and 3 Reclaimed sub-models, and the sub-models were simulated in a sequence of upstream to downstream based on its connectivity. The hydrologic calibration and validation of the model were conducted from 14 flow stations for the period of 2009 and 2013 using an automatic calibration scheme. The model performance to the hydrologic stations for calibration and validation showed that the Nash-Sutcliffe coefficient (NSE) ranged from 0.66 to 0.97, PBIAS were -31.0~16.5 %, and $R^2$ were from 0.75 to 0.98, respectively in a monthly time step and therefore, the model showed its hydrological applicability to the watershed. The water quality calibration and validation were conducted based on the 29 stations with the water quality constituents of DO, BOD, TN, and TP during the same period with the flow. The water quality model were manually calibrated, and generally showed an applicability by resulting reasonable variability and seasonality, although some exceptional simulation results were identified in some upstream stations under low-flow conditions. The spatial subdivision in the model framework were compared with previous studies to assess the consideration of administrative boundaries for watershed delineation, and this study outperformed in flow, but showed a similar level of model performance in water quality. The framework presented here can be applicable in a regional scale watershed as well as in a need of fine-resolution simulation.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.509-514
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• 2005

Geumgang canal is planned to connect Geumgang lake with Saemangeum reservoir to accelerate desalinization and dillute polluted water in Saemangeum reservoir. The purpose of this study is to evaluate the variations of water quality by divesion of Geumgang lake flow to the Saemangeum reservoir. WASP5 model was used to estimate water quality concentration of Geumgang lake. Model calibration and verification was done for water quality data for 2001 and 2002. As a result of simulating water quality concentration for 4 scenarios, which was considered whether Geumgang canal will be built, there was little influence on water quality in Geumgang lake though Geumgang lake flow diverted to Saemangeum reservoir.

• 대한토목학회논문집
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• 제29권5B호
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• pp.419-427
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• 2009

기존의 WTP를 이용한 수질개선 관련 편익산정 연구들은 특정 하천에 대하여 '모든 종류의 물놀이 가능한 2급수로 개선', '수영가능수준으로 개선' 등을 설문대상으로 하여 지불의사를 산정한 다음, 해당 유역의 가구수를 곱하여 편익으로 산정하였다. 이는 특정 수자원개발사업에 대한 편익이 아니며, 설문작성 과정에서 수질개선 정도에 대한 객관적인 설명이 부족하고, 단순화되었기 때문에 설문응답자들에게 설문대상재화에 대한 정보를 전달하는데 미흡한 점이 있었다. 따라서 본 연구에서는 수자원개발사업시 상수도 원수수질개선에 대한 편익/비용분석에 적용할 수 있는 편익산정방법론을 제시하였다. 본 연구에서는 수도권을 대상으로 하여 용수를 사용하는 소비자의 BOD 개선정도별 지불의사(WTP)를 설문을 조사하고, 설문결과를 통계분석하여 수질개선-지불의사 관계식을 도출하였다. 사례연구로서 낙동강수계의 내성천 지방2급하천 구간에 계획한 송리원 다목적댐을 대상으로 적용하였다. 방류시나리오별 연평균편익산정 결과, 연평균계획방류량($4.79m^3/s$) 방류시 5,980 백만원, 풍수기(7~10월)를 제외한 기간의 계획방류량($7.22m^3/s$) 방류시 8,663 백만원, 수질악화기 계획방류량($10.72m^3/s$) 방류시 11,905 백만원, 최대계획방류량($13.54m^3/s$) 방류시 14,502 백만원으로 산정되었다. 본 연구에서 개발된 가구소득별 수질개선 (BOD)-지불의사(WTP) 관계식을 이용함으로써 수질개선사업에 대한 원수수질편익을 산정할 때 수질개선정도에 상관없이 쉽게 편익을 산정할 수 있을 것으로 판단된다.